Gas burner control apparatus for operating a piezoelectric ignition system in conjunction with the gas valves

ABSTRACT

A VALVE HOUSING INCLUDES A PILOT VALVE AND A MAIN VALVE MOVABLE ALONG A COMMON AXIS TO OPEN AND CLOSE THE VALVES. AN OPEATING MECHANISM FOR THE VALVES INCLUDES A CAM SUPPORT AND A CAM POST CONTACTING A CAM ON ONE SIDE OF THE SUPPORT. A HANDLE IS OPERATIVELY CONNECTED TO THE SUPPORT SO THAT IT CAN BE ROTATED TO A POSITION AT WHICH THE PILOT VALVE IS OPEN. THE BURNING OF THE PILOT VALVE CAUSES A LATCH TO HOLD THE SUPPORT IN THE ROTATED POSITION. REVERSE ROTATION OF THE POST, CAMS THE ROTATIONALLY LATCHED SUPPORT SO AS TO OPEN THE MAIN VALVE. A HANDLE IS CONNECTED TO ROTATE THE POST AND ALSO A RING GEAR. AXIAL DISPLACEMENT OF THE HANDLE AXIALLY MOVES THE GEAR TO A POSITION AT WHICH IT ENGAGES A GEAR ON A PIEZOELECTRIC LIGHTER, WHEREUPON ROTATION OF THE TWO GEARS ACTUATES THE LIGHTER.

y 11, 1972 G MOBUS 3,676,041

GAS BURNER CONTROL APPARATUS FOR OPERATING A PIEZOELECTRIC IGNITION SYSTEM IN CONJUNCTION WITH THE GAS VALVES Filed Sept. 16. 1970 I NVEN TOR Gag/ 755 M05 US 060%; PM :2

United States Patent m GAS BURNER CONTROL APPARATUS FOR OPERATING A PIEZOELECTRIC IGNITION SYSTEM IN CONJUNCTION WITH THE GAS VALVES Gunter Mobus, Wermelskirchen, Germany, assignor to Job. Vaillant KG, Remscheid, Germany Filed Sept. 16, 1970, Ser. No. 72,638 Claims priority, application Austria, Sept. 26, 1969, A 9,151/ 69 Int. Cl. F2311 9/08 US. Cl. 431-47 11 Claims ABSTRACT OF THE DISCLOSURE A valve housing includes a pilot valve and a main valve movable along a common axis to open and close the valves. An operating mechanism for the valves includes a cam support and a cam post contacting a cam on one side of the support. A handle is operatively connected to the support so that it can be rotated to a position at which the pilot valve is open. The burning of the pilot valve causes a latch to hold the support in the rotated position. Reverse rotation of the post, cams the rotationally latched support so as to open the main valve. A handle is connected to rotate the post and also a ring gear. Axial displacement of the handle axially moves the gear to a position at which it engages a gear on a piezoelectric lighter, whereupon rotation of the two gears actuates the lighter.

BACKGROUND AND SUMMARY OF THE INVENTION The prior art (application Ser. No. 864,806, filed Oct. 8, 1969 and now Pat. No. 3,588,553 includes a piezoelectric ignition system, comprising a piezoelectric element, connected to a spark gap, and a handle by which an impact member can be retracted against spring biasing and then released to achieve a spring urged rapid forward movement of said impact element for producing an impact on the piezoelectric element. The handle is rotatable and the impact member is joined thereto in an unrotatable but axially slidable manner. The impact member has a driver which rides on sawtooth curves, extending axially and being fixed relative to the housing. During the handle rotation the driver is rotated with respect to the curves so that the curves move the driver and the impact member axially to retract the impact member. The impact takes place after the driver slides over the steep edge of the sawtooth curve and the member is free to move against the element under the urging of the spring. The movement takes place in a precisely-defined manner and with a precisely-defined angular position of the handle. The handle takes the form of a rotary handle which can be directly rotated by hand.

The prior art also includes gas-heated apparatus, for example gas water heaters, in which an ignition safety device is provided and the gas supply to a pilot burner is released by a rotary gas control having a pilot gas valve and a main gas valve coaxially disposed thereon. See, for example, application Ser. No. 767,265 filed Oct. 14, 1968 and now Pat. No. 3,550,603. The pilot burner may be ignited and a thermoelectric ignition safety device thereby brought into operation. Further rotation of the rotary gas control enables the main gas valve to be opened. In known rotary gas controls of the kind heretofore described, the displacement of the valve shank is controlled by a cam support which co-operates with a control member mounted on a rotary handle. In a known construction of this kind, the cam support for opening the pilot gas 3,676,041 Patented July 11, 1972 valve is entrained by the control cam due to rotation of the handle and is retained against the action of a return spring by means of an interlocking mechanism, operated by a retaining element from a heat-sensitive apparatus. In the known system, the cam support is provided with a claw, having an inclined surface which, when the cam support is rotated, displaces a retaining member, mounted on a bolt lever, relative to a thermally-sensitive apparatus in the form of a thermoelectrically energized magnet and the bolt lever retains the cam support in the rotated position by engagement into the claw of a pin mounted on the bolt lever, when the retaining member is retained in position. When the rotary handle is rotated in the reverse direction, the main gas valve is opened by a further axial displacement of the rotationally locked cam support by virtue of the fact that the control member of the rotary handle slides on a cam of the cam support.

Apparatus of the kind heretofore described is therefore provided with a rotary handle for the rotary gas control by means of which the pilot gas valve and main gas valve are controlled. An additional rotary handle would be required if such apparatus were to be provided with piezoelectric ignition means of the type previously described. This would not only impair the appearance of the apparatus, but would also render its operation more difficult since during the ignition operation one would be required to simultaneously operate two rotary handles in a defined, timed sequence. With a rotary gas control of the type previously mentioned, it would be necessary for the rotary control to be held by one hand in the ignition position until the thermoelectric ignition safety device responds and the cam support of the rotary gas control is locked in place. With the other hand one would have to operate the rotary handle of the piezoelectric ignition device while the rotary handle of the gas control is held in the ignition position.

It is the object of the invention to simplify the operation of apparatus having a piezoelectric ignition device of the type previously described.

According to the invention this is achieved in that the ignition device is disposed axially parallel and adjacent to a rotary gas control; the gas control is provided with coaxial plate valves which can be thrust open by means of a rotary handle via a control cam (or control cams); and the rotary handle on the gas valve is provided with serrations which engage with serrations of the rotary handle on the ignition device for producing an ignition pulse after opening the pilot valve.

According to the invention only a single rotary handle is therefore provided for operating the rotary gas control and the piezoelectric ignition device. The invention utilizes the fact that operation of a piezoelectric ignition device of the type of the above application is performed by a rotating motion so that operation of the piezoelectric ignition device can be derived from the rotating motion of the rotary handle of the rotary gas control. The invention furthermore utilizes the fact that in the construction according to the application, the impact is triggered at a precisely defined angular position of the handle so that the ignition spark can be triggered exactly at the correct time after opening the pilot valve when the rotary gas control and the ignition device are coupled in the manner described hereinabove.

Depending on the construction of the rotary gas control, the rotating handle thereof and the ignition device handle can be constantly coupled if the aforementioned rotating handle requires rotation in only one direction. It is also possible for a free-wheeling clutch to be provided between the rotating handle of the rotary gas control and the piezoelectric ignition device.

A particularly simple construction is obtained by an arrangement in which the rotating handle can be axially depressed with the serrations being in engagement with each other only when the handle is so depressed. It is then possible for the rotary :gas control to be provided in known manner with a cam support which, for opening the pilot valve, is entrained by rotation of the rotating handle and through a control cam rotating therewith and is retained against the action of a return spring by interlocking means, operated from a heat-sensitive device by means of a retaining element, and that reverse rotation of the rotating handle is accompanied by a further axial displacement of the interlocked cam support, causing the main gas valve to open, namely in that the control member of the rotating handle slides on a cam track of the cam support. The control member is mounted on a disc which is rotatably mounted in the housing, and a handle, provided with external serrations may be unrotatably disposed on a central pin but may be adapted to be axially slidable against the action of a compression spring.

DESCRIPTIGN OF THE DRAWINGS FIG. 1 is a diagrammatic view of a vertical section through the rotary gas control;

FIG. 2 shows, also in diagrammatic form, a section through the gas housing along the line C-D of FIG. 1 and with the thermoelectric magnet;

FIG. 3 shows the rotary gas control and the piezoelectric ignition device coupled thereto, also in diagrammatic form and as a horizontal section along the lines A-B of FIG. 1;

FIG. 4 shows in diagrammatic form the rotating handle of the gas control in the inoperative state;

FIG. 5 shows the handle in the ignition position; and

FIG. 6 shows the handle in the operating position.

DESCRIPTION OF SPECIFIC EMBODIMENT The following disclosure is ofiered for public dissemination in return for the grant of a patent. Although it is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose, as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

A spring-loaded pilot valve 2 and an equally springloaded main gas valve 3 are coaxially disposed in a .valve housing 1. They are opened successively by a valve operating mechanism. This mechanism includes a valve shank 4 having a driver 4' which are axially displaced during the valve opening operation. A pilot gas line 5 leading to pilot burner 33 branches off between the valves 2 and 3.

A cam follower 6 on the end of the valve shank 4 bears against a cam track 19' on a cam support 7. Cam support 7 is mounted in a control housing 8 so as to be rotatable and axially slidable. A rotating plate 9 is rotatably supported in the control housing 8 but is restrained against axial movement. It has a cam post 10 and a driver pin 11. A rotating handle 12 has a sleeve 13 which receives driver pin 11. Driver pin 11 has splines 11 which rotationally engage sleeve 13 while permitting axial movement between the two. An inwardly flange 13' of the sleeve 13 contacts splines 11' to limit the outwardly axial movement of the handle 12 in response to the urging of compression spring 14.

-A claw 15, extending radially outside the control housing 8 and having a hook-shaped extension 16 and an inclined surface 17, is mounted on the cam support 7. A helical spring 18 tends to rotate the cam support 7 in a clockwise direction. A stop abutment surface 7' on the cam support is contacted by the cam post 10 of the rotatable disc 9. When the disc 9 is rotated counterclockwise from the zero position illustrated in FIG. 1 by moving the rotating handle 12, the cam support 7 is correspondingly rotated by contact with the cam post 10. This tensions the helical spring 18 and cam face 19 moves follower 6 sufficiently to the left (in FIGS. 1 and 3) so that the pilot gas valve 2 is opened.

During this rotation of the cam support 7, the claw 16 is moved from the broken-line position indicated in FIG. 2 toward the full line position. There cam face 17 bears against a pin 23 on lever 21. Lever 21 is pivotally mounted on the housing at 20 and is urged in a clockwise direction by spring 22. When the lever is pivoted in the opposite direction against the urging of the spring by reason of cam 17 pressing on pin 23, armature 25 is moved to the core of electromagnet 26. The electromagnet 26 is energized in known manner by the thermally induced current from a thermocouple 28 disposed in the zone of the pilot flame 27. These elements thus form a latching device for the cam support 7.

At its outer edge the rotating handle 12 has a ring gear 29. The adjacent rotating handle 30 of the piezo electric ignition device 31 also has a ring gear 32. To put the burner into operation, the rotating handle 12 is depressed while in the zero position (FIG. 4) against the force exerted by the spring 14. This causes meshing of ring gears 29 and 32. The handle 12 is then rotated from the zero position in a counterclockwise direction (against the force exerted by the helical spring 18) into the position I (FIG. 5) and held in that position. This results in the pilot gas valve 2 being raised from its seat so that pilot gas is discharged at the pilot burner head 33. The same rotation of handle 12 also drives handle 30 through the gear drive 29, 32 to actuate the igniter 31 and produce an electric spark on the ignition electrode 34 to ignite the pilot flame 27. The handle 12 is held in the ignition position I until the magnet 26 is sufiiciently energized, by the heating of the thermocouple 28, to retain the armature 25 and the lever 21 in the depressed position. In this depressed position pin 23 is behind abutment 16 of claw 15 so that the cam support 7 is latched in the control position I (FIG. 5) while the helical spring 18 is stressed. Being so latched, the cam support 7 cannot return into its starting position even when the rotating handle is released. However, when the ignition flame 27 is extinguished and there is no current supplied to electromagnet 26 it is able to do so.

If the inwardly pressed handle 12 is allowed to return outwardly by the urging of spring 14 when the cam support 7 is so latched, the gear transmission will disengage and the handle 12 then can be returned in the clockwise direction from the control position I illustrated in FIG. 5 into the control position 11 illustrated in FIG. 6. With the rotation, the cam post 10 of the rotating part 9 slides along a cam track portion 36 of the cam support 7 until it reaches a ratchet surface portion 37. This causes the cam support 7 to be axially displaced inwardly (to the left in FIGS. 1 and 3) in the control housing 8. The inward movement of cam support 7 forces cam follower 6 a corresponding additional increment so that driver 4' will open the main gas valve 3 in addition to pilot valve 2. This axial displacement of the cam support 7 causes the claw 15 to slide axially on the pin 23 of the latching lever 21 so that the latching of the cam support 7 is retained. The changeover from the control position I to the control position II, that is to say, opening and closing of the main gas valve 3 may, of course, be repeated at will.

The rotating handle also can be moved from the O position (FIG. 4) into position I (FIG. 5) as often as is desired.

It is possible for air to be disposed in the pilot gas pipe 5 of the pilot burner. If this condition is noted when the system is put into operation, it is possible, without depressing the handle 12, to initially rotate it into the ignition position I and to allow the gas to force the air out for a few seconds before initiating the ignition process by depressing and rotating the handle.

However, if the handle 12 is returned beyond the control position H (FIG. 6) into the position (FIG. 4) while the cam support '7 is latched, the cam post will slide beyond the ratchet surface portion 37 onto a further cam track portion 38 to result in an additional axial displacement of the cam support 7. The claw will then slide off the leading end of the pin 23 unlatching the cam support. Due to the effect of the stressed helical spring 1-8, the cam support 7 then returns into its starting position at which both valves 2 and 3 are closed. The flames will go out, but before the gas can be turned on again the thermocouple 28 must cool sufliciently to de-energize electromagnet 26 and thereby release lever 21. When the looking lever 21 then returns into its starting position due to the action of the return spring 22, it becomes possible to move the handle 12 and cam support to the position illustrated in FIG. 5. A retaining element, for example, a bimetallic strip heated by the ignition flame 27 and released when the ignition flame is extinguished, may be employed instead of the magnet armature and the magnet 26.

The piezoelectric ignition device, generally 31, is of tubular construction. It is aflixed to the gas control housing 1, 8 by supports 38. The piezoelectric ignition element 39 is thrust by a spring washer 40 against an anvil 41 which in turn bears on the base 42 0f the tube housing 43. The striker pin 44 of the element extends through the spring washer 40. The striker 45 is biased against the striker bolt by a spring 46. The other end of the tubular housing 43 has sawtooth cams 47. These cams form inclined planes 48 and axially parallel edges 49 between the inclined planes 48. These sawtooth cams are disposed directly opposite to each other on the tubular housing. A cam follower 52 (in the form of a transverse pin) is connected to striker rod 45' and rides on sawtooth cam 47. Through a central post 50 of handle the follower 52 is rotated with the handle while permitting the follower and rod 45' to move axially in casing 43. Handle 30, while rotatable, is restrained against movement axially of the casing. As the handle 30 is rotated the follower 52 also is rotated causing it to move outwardly (to the right in FIG. 3) along the inclined cam surfaces 48. The movement of the follower 52 results in a corresponding movement of striker 45 so that it retracts from pin 44 against the urging of spring 46. When follower 52 reaches the axially parallel edges 49 the cam follower and striker are free to move inwardly (to the left in FIG. 3) as a result of the urging of spring 46. Thus, at a precisely defined instant with respect to the rotational position of handle 30, the striker is freed to produce a blow on pin 44 of the piezoelectric element. The blow on pin 44 causes the piezoelectric element top roduce a high voltage electric impulse which is supplied via the cable 39 to the ignition electrode 34 and produces an ignition spark which ignites the pilot flame 27. As previously described, the handle 30 is rotated by handle 12 through the interengaging gearing so that the timing of the spark is coordinated with the operation of the gas valves by handle 12.

The construction described hereinabove also has the following important advantage:

The cam support 7 has a latching mechanism including a retaining claw 15 which, on the one hand, has an inclined surface by means of which, and when the cam support 7 is rotated, the magnet armature mounted on the latching lever 21. is thrust against the thermoelectrically energized magnet 26, the pin 23 of the latching lever retaining the cam support in the rotated position by engaging in the claw. On the other hand, the retaining claw has an extension 16 having a straight external edge forming an abutment. The pin 23 of the locking lever 21 strikes the external edge in the event of directly successive switching off and switching on again of the gas valves, when the magnet armature 25 is still retained. This not only prevents rotation of the cam support into the ignition position but also prevents the triggering of an ignition spark which could explosively ignite a combustible gas mixture which could still be present in the apparatus.

I claim:

1. In a gas burner control apparatus comprising a gas valve device for controlling the flow of gas to a pilot burner and independently the flow of gas to a main burner and a piezoelectric ignition device having a member which is rotated about a first axis to actuate the generation of electricity, the improvement comprising:

said gas valve device including a manually operable handle rotatable about a second axis for operating said valve device;

means connecting said devices and positioning the de- 'vices with respect to each other in a manner such that said axes are parallel; and

means for rotatably connecting said handle and said member and including a gear on the member and a gear on the handle.

2. In an apparatus as set forth in claim 1, wherein said gas valve device includes a housing, two gas valves within said housing and coaxially positioned, one of said valves being the pilot gas valve and the other being a main gas valve, actuating means for said valves including a rotatable cam device and means for connecting said cam device to said handle.

3. In an apparatus as set forth in claim 2, wherein said handle is mounted for axial movement along said second axis from a first axial position to a second axial position,

said gear on said member being positioned opposite and engaging said gear on said handle when the handle is in the second position with the two gears being axially spaced apart when the handle is in the first position.

4. In an apparatus as set forth in claim 3, including spring means for resiliently urging said handle towards the first position.

5. In an apparatus as set forth in claim 3, wherein said gas valve device has a rotatable cam support with cam tracks on opposite axial ends thereof,

said actuating means comprises a cam post contacting the cam track on one end and rotatably connected to said handle, means restraining said cam post against axial movement, latching means for holding said support in a rotated position and having one portion on said support and a second portion on the housing and releasably engageable with each other, said latching means being responsive to the presence of a pilot flame, said cam track on said one end having a stop abutment surface so that when said post is rotated in one direction it comes against said stop abutment surface and causes rotation of the support, said cam track on said one end having an inclined surface adjacent said stop abutment surface so that when said post is rotated in the opposite direction and said support is latched against rotation said post will move up said incline and move said support in axial direction from a first axial position to a second axial position, said actuating means opening said main gas valve when said support moves to said second axial position.

6. In a device as set forth in claim 5, wherein said actuating means includes a disc rotatably mounted on said housing and restrained against axial movement, said post being mounted on one axial side of said disc, said handle being at the other axial side of said disc, means connecting said disc and handle for common rotational movement while permitting the handle to move axially with respect to the disc.

7. In an apparatus as set forth in claim 6 including a compression spring between the disc and the handle resiliently urging the handle towards said first axial position.

8. In an apparatus as set forth in claim 7, wherein said one portion of said latching means comprises a retaining claw having an inclined surface and an abutment;

said second portion comprises a locking lever pivotally mounted at one end thereof and a cross pin at the other end of the locking lever, said lever being positioned for the inclined surface to contact the pin and push the pin and move the lever to a locking position at which the pin is behind the abutment when the support is moved to the rotated position by said post, thereby retaining the support in the rotated position so long as the pin remains latched behind the abutment;

thermoelectric means for retaining the lever in the position at which the pin is behind the abutment so long as the pilot flame is burning, said thermoelectric means having a part on said lever and a part positioned to be affected by the pilot burner flame; and

said abutment having a distal surface to contact the pin and thereby block the movement of the claw toward latching position when the lever is in the locking position.

9. In an apparatus as set forth in claim 5, wherein said one portion of said latching means comprises a retaining claw having an inclined surface and an abutment;

said second portion comprises a locking lever pivotally mounted at one end thereof and a cross pin at the other end of the locking lever, said lever being positioned for the inclined surface to contact the pin and push the pin and move the lever to a locking position at which the pin is behind the abutment when the support is moved to the rotated position by said post, thereby retaining the support in the rotated position so long as the pin remains latched behind the abutment;

thermoelectric means for retaining the lever in the position at which the pin is behind the abutment so long as the pilot flame is burning, said thermoelectric means having a part on said lever and a part positioned to be affected by the pilot burner flame; and

said abutment having a distal surface to contact the pin and thereby block the movement of the claw toward latching position when the lever is in the locking position.

10. In an apparatus as set forth in claim 2,

wherein said ignition device is actuated upon the rotation of said member through a given angle, and

wherein said pilot valve is opened to result in the flow of gas from the pilot burner upon the rotation of said cam device through a predetermined angle, and

wherein said rotatable connecting means has a gearing ratio such that when the gears are engaged and said handle is rotated sufficiently to move said member through said given angle said cam device will have been rotated through said predetermined angle.

11. In an apparatus as set forth in claim 10,

including latching means for engaging and holding said cam device after it has been rotated through said predetermined angle and said pilot flame has heated a thermosensitive element forming a part of the latching means, said latching means also including a stop to prevent said cam device from being rotated through said given angle from its initial position when said thermosensitive element is heated.

References Cited UNITED STATES PATENTS 2,607,406 8/ 1952 Caparone 431-47 3,434,790 3/ 1969 Jsao Kanda 4311-355 3,550,603 12/ 1970 Schueler 137-66 CARROLL B. DORIT Y, JR., Primary Examiner U.S. Cl. X.R. 

